Blockly.Blocks['duck1'] = {
    init: function() {
      this.appendDummyInput()
          .appendField(new Blockly.FieldImage("../res1/duck1.png", 300, 100, "*"));
      this.setPreviousStatement(true, null);
      this.setNextStatement(true, null);
      this.setColour(330);
   this.setTooltip("");
   this.setHelpUrl("");
    }
  };

  Blockly.Blocks['duck2'] = {
    init: function() {
      this.appendDummyInput()
          .appendField(new Blockly.FieldImage("../res1/duck2.png", 300, 100, "*"));
      this.setPreviousStatement(true, null);
      this.setNextStatement(true, null);
      this.setColour(330);
   this.setTooltip("");
   this.setHelpUrl("");
    }
  };

  Blockly.Blocks['duck3'] = {
    init: function() {
      this.appendDummyInput()
          .appendField(new Blockly.FieldImage("../res1/duck3.png", 300, 100, "*"));
      this.setPreviousStatement(true, null);
      this.setNextStatement(true, null);
      this.setColour(330);
   this.setTooltip("");
   this.setHelpUrl("");
    }
  };

  Blockly.JavaScript['duck1'] = function(block) {
    // TODO: Assemble JavaScript into code variable.
    var code = "#duck1";
    return code;
  };

  Blockly.JavaScript['duck2'] = function(block) {
    // TODO: Assemble JavaScript into code variable.
    var code = '#duck2';
    return code;
  };

  Blockly.JavaScript['duck3'] = function(block) {
    // TODO: Assemble JavaScript into code variable.
    var code = '#duck3';
    return code;
  };